In a large mixing bowl, add the room temperature cream cheese, pumpkin puree, instant vanilla pudding mix, and pumpkin pie spice blend. Blend everything together with a hand mixer on medium speed until the mixture is smooth and creamy with no lumps remaining.

Gently fold the thawed whipped topping into the pumpkin mixture from Step 1, using a spatula. Mix until everything is fully combined and the texture is light and fluffy. I like to fold gently to keep the mousse airy and avoid deflating the whipped topping.

Transfer the pumpkin mousse to a serving bowl or individual cups. Refrigerate for at least 1 hour before serving to allow the flavors to meld and the mousse to set up nicely.